High aperture LCD with insulating color filters overlapping bus lines on active substrate

ABSTRACT

A high aperture active matrix liquid crystal display (AMLCD) includes pixel electrodes in respective pixels which overlap adjacent address lines. The color filters are formed on the active substrate in a manner such that the filters also overlap the address lines and function as an insulating layer between the pixel electrodes and address lines in the areas of overlap. Accordingly, line-pixel capacitances are reduced and the resulting AMLCD is easier to manufacture. The total number of process step in manufacturing is reduced, and plate-to-plate (active to passive plate) alignment is much easier and less important.

[0001] This application is a continuation-in-part (CIP) of U.S. Ser.Nos. 08/630,984, filed Apr. 12, 1996; and a CIP of 08/470,271, filedJun. 6, 1995 entitled LCD WITH INCREASED PIXEL OPENING SIZES, and a CIPof 08/671,376, filed Jun. 27, 1996, the disclosures of which are allhereby incorporated herein by reference. Also, this application isrelated to commonly owned U.S. Pat. No. 5,641,974, and Ser. No.08/832,345, the disclosures of which are incorporated herein byreference.

[0002] This invention relates to a liquid crystal display (LCD) havingan increased pixel aperture ratio and different colored polymer filters.More particularly, this invention relates to a liquid crystal displayincluding an array of TFTs wherein photo-imageable color filters havingcontact vias or apertures disposed therein are located on the activesubstrate between the address lines and pixel electrodes so that thepixel electrodes and color filters may both be permitted to overlap atleast one of the row and column address lines without exposing thesystem to capacitive cross-talk, thereby providing an efficient andcommercially improved high aperture LCD.

BACKGROUND OF THE INVENTION

[0003] Electronic matrix arrays find considerable application in X-rayimage sensors and active matrix liquid crystal displays (AMLCDs). SuchAMLCDs generally include X and Y (or row and column) address lines whichare horizontally and vertically spaced apart and cross at an angle toone another thereby forming a plurality of crossover points. Associatedwith each crossover point is an element (e.g. pixel) to be selectivelyaddressed. These elements in many instances are liquid crystal displaypixels or alternatively the memory cells or pixels of an electronicallyadjustable memory array or X-ray sensor array.

[0004] Typically, a switching or isolation device such as a diode orthin-film transistor (TFT) is associated with each array element orpixel. The isolation devices permit the individual pixels to beselectively addressed by the application of suitable potentials betweenrespective pairs of the X and Y address lines. Thus, the TFTs act asswitching elements for energizing or otherwise addressing correspondingpixel electrodes.

[0005] Amorphous silicon (a-Si) TFTs have found wide usage for isolationdevices in liquid crystal display (LCD) arrays. Structurally, TFTsgenerally include substantially co-planar source and drain electrodes, athin-film semiconductor material (e.g. a-Si) disposed between the sourceand drain electrodes, and a gate electrode in proximity to thesemiconductor but electrically insulated therefrom by a gate insulator.Current flow through the TFT between the source and drain is controlledby the application of voltage to the gate electrode. The voltage to thegate electrode produces an electric field which accumulates a chargedregion near the semiconductor-gate insulator interface. This chargedregion forms a current conducting channel in the semiconductor throughwhich current is conducted. Thus, by controlling the voltage to the gateand drain electrodes, the pixels of an AMLCD may be switched on and offin a known manner.

[0006] Typically, pixel aperture ratios (i.e. pixel openings) innon-overlapping AMLCDs are only about 50% or less. As a result, eitherdisplay luminance is limited or backlight power consumption isexcessive, thereby precluding or limiting use in certain applications.Thus, it is known in the art that it is desirable to increase the pixelaperture ratio or pixel opening size of LCDs to as high a value aspossible so as to circumvent these problems. The higher the pixelaperture ratio (or pixel opening size) of a display, for example, thehigher the display transmission. Thus, by increasing the pixel apertureratio of a display, transmission may be increased using the samebacklight power, or alternatively, the backlight power consumption maybe reduced while maintaining the same display luminance.

[0007] It is known to overlap pixel electrodes over address lines inorder to increase the pixel aperture ratio. For example,

[0008] “High-Aperture TFT Array Structures” by K. Suzuki discusses anLCD having an ITO shield plane configuration having a pixel apertureratio of 40% and pixel electrodes which overlap signal bus lines. An ITOpattern in Suzuki located between the pixel electrodes and the signallines functions as a ground plane so as to reduce coupling capacitancebetween the signal lines and the pixel electrode. Unfortunately, it isnot always desirable to have a shield electrode disposed along thelength of the signal lines as in Suzuki due to production and costconsiderations. The disposition of the shield layer as described bySuzuki requires extra processing steps and thus presents yield problems.Accordingly, there exists a need in the art for a color LCD with anincreased pixel aperture ratio which does not require an ITO shieldplane structure to be disposed between the signal lines and pixelelectrode.

[0009] It is old and well-known to make TFT arrays for LCDs whereinaddress lines and overlapping pixel electrodes are insulated from oneanother by an insulating layer. For example, see U.S. Pat. Nos.5,055,899; 5,182,620; 5,414,547; 5,426,523; 5,446,562; 5,453,857; and5,457,553.

[0010] U.S. Pat. No. 5,182,620 discloses an AMLCD including pixelelectrodes which at least partially overlay the address lines andadditional capacitor lines thereby achieving a larger numerical aperturefor the display. The pixel electrodes are insulated from the addresslines which they overlap by an insulating layer formed of silicon oxideor silicon nitride. Unfortunately, the method of making this display aswell as the resulting structure are less than desirable because: (i)chemical vapor deposition (CVD) is required to deposit the silicon oxideor silicon nitride insulating film; (ii) silicon oxide and siliconnitride are not photo-imageable (i.e. contact holes or vias must beformed in such insulating layers by way of etching); and/or (iii) thedielectric constants of these materials are too high and thereby renderthe LCD susceptible to cross-talk problems. Still further, the '620patent does not discuss or contemplate color filter issues. As a resultof these problems, the manufacturing process is both expensive andrequires more steps than would be otherwise desirable. For example, inorder to etch the contact holes in an insulating layer, an additionalphotoresist coating step is required and the user must be concernedabout layers underneath the insulating layer during etching. Withrespect to CVD, this is a deposition process requiring expensiveequipment. Furthermore, if the color filters are on the passivesubstrate, as they typically are, alignment of the active and passiveplates is difficult and requires expensive equipment and expertise.

[0011] In the prior art, color filters in active matrix liquid crystaldisplays (AMLCDs) are typically located on the substrate (the passiveplate or substrate) which opposes the active matrix substrate. In otherwords, the color filters and TFTs (or diodes) are typically located ondifferent substrates, on opposite sides of the liquid crystal (LC) layer[e.g. see U.S. Pat. No. 5,499,126]. Black matrix formation is alsotypically provided on the color filter substrate. The provisions of theblack matrix and color filters on the substrate opposite the activematrix is, of course, costly, time consuming, and requires numerousmanufacturing steps. As discussed above, this also requires difficultand time consuming alignment steps.

[0012] The LCD structure disclosed in U.S. Pat. No. 5,641,974 utilizes atransparent polymer insulating layer on the active substrate to provideisolation between address lines and overlapping pixel electrodes. Whilethis design work well and achieves superior results, it unfortunately,in practice, requires each of: (i) providing the transparent polymerinsulating layer on the active substrate; (ii) providing color filterson the opposite substrate; (iii) providing a black matrix on the colorfilter substrate; (iv) very accurate plate-to-plate (i.e.substrate-to-substrate) alignment; and (v) the process steps requiredfor (ii)-(iv) above.

[0013] It is apparent from the above that there exists a need in the artfor an improved high aperture AMLCD design, and method of manufacturingsame, which (i) reduces the number of total manufacturing process stepsrequired; (ii) eliminates the need for the combination of (a) theoptically transparent insulating layer sandwiched between the addresslines and pixel electrodes, and (b) the color filters; (iii) reduces theneed for the black matrix on the substrate opposite the activesubstrate; (iv) provides for a high pixel aperture ratio; and/or (v)reduces the accuracy required in plate-to-plate alignment (i.e.eliminates the need for sophisticated alignment machines).

[0014] It is a purpose of this invention to fulfill the above-describedneeds in the art, as well as other needs which will become apparent tothe skilled artisan from the following detailed description of thisinvention.

SUMMARY OF THE INVENTION

[0015] Generally speaking, this invention fulfills the above-describedneeds in the art by providing a high aperture color LCD including colorfilters, the display comprising:

[0016] first and second substrates;

[0017] a liquid crystal layer sandwiched between the first and secondsubstrates;

[0018] first and second different colored pixels, said first pixelincluding on said first substrate a first pixel electrode, a firstinsulating color filter, and a first thin film transistor (TFT), andsaid second pixel including on the first substrate a second pixelelectrode, a second insulating color filter, and a second TFT, whereinsaid first and second color filters are differently colored;

[0019] the first and second pixel electrodes overlapping withcorresponding address lines in communication with TFTs so as to define ahigh aperture display, the overlapping forming areas of overlap;

[0020] the first insulating color filter being at least partiallydisposed in an area of overlap in the first pixel, the first colorfilter having a dielectric constant of less than about 5.0 and having afirst contact hole defined therein that allows the first pixel electrodeto be electrically connected to the first TFT; and

[0021] said second insulating color filter being at least partiallydisposed in an area of overlap in the second pixel, the second colorfilter having a dielectric constant less than about 5.0 and having asecond contact hole defined therein that allows the second pixelelectrode to be electrically connected to the second TFT.

[0022] In certain embodiments, each of the first and second colorfilters are of a photo-imageable material that includes a color dye orpigment.

[0023] In certain embodiments, the LCD includes arrays of only twocolored pixels, while in other embodiments the display may includearrays of three differently colored pixels, or four differently coloredpixels.

[0024] Surprisingly, it has been found that the thickness of the metalpixel electrode layers (e.g. ITO) should be from about 300 Å-900Å(preferably about 600 Å) in this invention in order to reduce theinterface stress between the pixel electrodes (e.g. ITO) and the colorfilters.

[0025] This invention further fulfills the above-described needs in theart by providing a method of making a color LCD having insulating colorfilters, the method comprising the steps of:

[0026] providing first and second substrates;

[0027] providing a liquid crystal material;

[0028] forming an array of isolation switching elements on the firstsubstrate and a plurality of address lines in communication with theisolation switching elements;

[0029] depositing a first resist color filter layer on the firstsubstrate over top of the address lines and the switching elements;

[0030] photo-imaging the first resist color filter layer so as topattern it into a first array on the first substrate so that colorfilters in the first array are of a first color and overlap at least aportion of at least one address line;

[0031] depositing a second resist color filter layer of a second colorover top of the first array of color filters;

[0032] photo-imaging the second resist color filter layer so as topattern it into a second array so that color filters in the second arrayoverlap at least a portion of at least one address line;

[0033] forming contact holes in color filters in each of the first andsecond arrays;

[0034] depositing a conductive pixel electrode layer over top of thefirst and second arrays of color filters; and

[0035] patterning the electrode layer so as to form an array ofsubstantially transparent pixel electrodes wherein pixel electrodes inthe array overlap address lines which are also overlapped by colorfilters so that the color filters act as insulators between the pixelelectrodes and the address lines in the areas of overlap, wherein eachof the pixel electrodes is in electrical communication with acorresponding switching element through one of the contact holes.

[0036] In certain preferred embodiments, each of the color filters has adielectric constant less than or equal to about 4.0 so as to reducecross-talk and coupling capacitance in the areas of overlap.

[0037] This invention will now be described with reference to certainembodiments thereof as illustrated in the following drawings.

IN THE DRAWINGS

[0038]FIG. 1 is a top view of an AMLCD active plate according to oneembodiment of this invention, this figure illustrating a plurality ofdifferent colored pixels wherein the illustrated pixel electrodes 3 andcorresponding color filters 101-104 are overlapping surrounding andproximate row and column address lines along their respective lengthsthroughout the pixel area so as to increase the pixel aperture ratio ofthe display.

[0039]FIG. 2 is a top view of the column or drain address lines andcorresponding drain electrodes of the AMLCD of FIG. 1, this figure alsoillustrating the TFT source electrodes disposed adjacent the drainelectrodes so as to define the respective TFT channels.

[0040]FIG. 3 is a top view of the pixel electrodes of FIG. 1 and thecorresponding insulating color filters, except for electrode extensions.

[0041]FIG. 4 is a side elevational cross-sectional view of a linearshaped TFT and corresponding color filter and pixel electrode of FIGS.1-3.

[0042]FIG. 5 is a side elevational cross-sectional view of the AMLCD ofFIGS. 1 and 4, except that this figure does not illustrate theinsulating color filters or TFTs.

[0043]FIG. 6(a) is a top view of an AMLCD active plate according toanother embodiment of this invention.

[0044]FIG. 6(b) is a side cross-sectional view of the FIG. 6(a) AMLCD,along A-A.

[0045]FIG. 6(c) is a side cross-sectional view of a portion of thedisplay according to the FIG. 6(a) along B-B, this embodimentillustrating the color filters and pixel electrodes overlappingrespective address lines and TFTs on the active matrix plate, thisembodiment differing from the previously illustrated FIG. 1 embodimentin that the gate electrode in this embodiment protrudes at a 90° anglefrom the gate line so as to be parallel to the drain line, in eachpixel.

[0046] FIGS. 7-10 are side elevational cross-sectional viewsillustrating how the active matrix in the display of FIG. 1 ismanufactured according to an embodiment of this invention.

[0047]FIG. 11 is a top view of an array of colored pixels, illustratingthe array of color filter strips extending across the viewing areaaccording to the FIG. 6 embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THIS INVENTION

[0048] Referring now more particularly to the accompanying drawings inwhich like reference numerals indicate like parts throughout the severalviews.

[0049]FIG. 1 is a top view of four different colored pixels (red, green,blue, and white) in an array on the active plate of an active matrixliquid crystal display (AMLCD) 2 according to an embodiment of thisinvention. This particular portion of the display includes an arraypixel electrodes 3, drain address lines 5, gate address lines 7, anarray of four thin-film transistors (TFTs) 9, auxiliary storagecapacitors 11, and finally insulating color filters 101-103 (theperipheries of these color filters are illustrated in broken or dottedlines) and optional substantially clear polymer layer 104. The colorlayer 104 defines white pixel (s). Each storage capacitor 11 is definedon one side by a gate line 7 and on the other side by an independentstorage capacitor electrode 12. Storage capacitor electrodes 12 areformed along with drain electrodes 13.

[0050] For example, the number of total process steps on the active andpassive plates is reduced, and the active to passive plate alignment ismuch easier and less important. In some embodiments, up to three or morephoto steps in manufacturing can be eliminated.

[0051] As shown, the longitudinally extending edges of each pixelelectrode 3 and each color filter 101-103 at least partially overlapboth drain lines 5 and gate lines 7, respectively, along edges thereofso as to increase the pixel aperture ratio (or pixel opening size) ofthe color AMLCD. The optically clear layer 104 in each white pixel alsooverlaps the address lines. Optionally, only one of the gate lines anddrain lines may be at least partially overlapped by the pixel electrodeand color filter of a given pixel.

[0052] The red, green, and blue pixels are provided with color filters101-103, respectively, while the white pixel may or may not be providedwith clear layer 104.

[0053] The areas of overlap between the address lines (e.g. gate and/ordrain) and the overlapping pixel electrodes and color filters arereferred to as overlap areas 18. In each of these areas 18 of overlapbetween the (i) address line(s) 5, 7, and (ii) pixel electrodes 3 andcolor filters 101-103 (and insulating layer 104), a pixel-line (PL)capacitor is defined by an electrode 3 on one side and the overlappedconductive address line 5, 7 on the other side. The dielectric disposedbetween the opposing electrodes of these PL capacitors is represented bythe insulating color filters 101-103 (e.g. see FIGS. 4 and 6) in thecolored pixels and layer 104 in white pixels. The parasitic capacitanceC_(PL) of these capacitors is defined by the known equation:

C _(PL)=∈·∈₀ ·A/d

[0054] where “d” is the thickness of the color filter layer, ∈ is thedielectric constant of the color filter, ∈₀ is the constant 8.85×10⁻¹⁴F/cm (permitivity in vacuum), and “A” is the area of the PL capacitor inthe overlap area 18 at issue. The fringing capacitance may also be takeninto consideration in a known manner. Also, according to certain otherembodiments, the color filters 101-103, and layer 104, are of a materialand thickness so that C_(PL) is less than or equal to about 0.01 pF fora display with a pixel pitch reference of about 150 μm. When the pixelpitch is smaller than this reference of 150 μm, C_(PL) should be scaledto a lower value as well because overlap area(s) 18 are smaller.Additionally, the pixel aperture ratio of the LCD decreases as the pixelpitch decreases, as is known in the art. The pixel pitch of AMLCD 2 maybe from about 40 to 5,000 μm according to certain embodiments of thisinvention. The pixel pitch, as known in the art, is the distance betweencenters of adjacent pixels in the array.

[0055] An important aspect of this invention is the fact that, asillustrated in FIG. 1, the color filters 101-103 (and layer 104) areprovided on the active matrix substrate (i.e. on the active plate), andact as insulators in these capacitors between overlapping pixelelectrodes 3 and address lines. Accordingly, the color filters 101-103and layer 104 are patterned on the active plate so that they alsooverlap the corresponding address lines so as to insulate them from theoverlapping pixel electrodes 3. The color filters 101-103 and layer 104are patterned on the active plate so that different color filters arespaced from one another, between adjacent pixels, by from about 0.5 to2.0 μm in certain embodiments. Thus, a gap “P” or space of this width isprovided over address lines between pixels, the gap “P” defined as thedistance between filters. This design simplifies the manufacturingprocess for forming the AMLCDs, and results in a more efficient displayand method of manufacture.

[0056] As illustrated in FIG. 1, color filter 101 is a red color filter,color filter 102 is a green color filter, color filter 103 is a bluecolor filter, and layer 104 is a substantially clear material as in U.S.Pat. No. 5,641,974). Each of color filters 101-103 is of aphoto-imageable material, with a respective color filter pigment addedthereto. Layer 104 may also be photoimageable. The colors of therespective filters 101-103 need not be limited to these particularcolors, but may also assume different colors in alternative embodimentsof this invention, as is known in the art. Alternatively,non-photo-imageable material may be used, with pigment or dye, as thecolor filters 101-103 and layer 104.

[0057]FIG. 2 is a top view of drain address lines 5 of the FIG. 1 AMLCD2 illustrating how extensions of address lines 5 form drain electrodes13 of TFTs 9. Each TFT 9 in the array includes source electrode 15,drain electrode 13, and corresponding gate electrode 17. Gate electrode17 of each TFT 9 is formed by the corresponding gate address line 7adjacent the TFT according to certain embodiments of this invention. Inother embodiments (e.g. see FIG. 6), gate electrode 17 for each TFT maybe formed by a branch extending substantially perpendicular to the gateaddress line. Herein, a source electrode is defined as the TFT electrodethat is in communication with the pixel electrode.

[0058]FIG. 3 is a top view illustrating pixel electrodes 3 in solidlines (absent their extension portions 38) and the corresponding colorfilters 101-103 in broken lines. FIGS. 2-3 are provided so that FIG. 1maybe more easily interpreted. As shown in FIG. 3, the exteriorperiphery of each color filter 101-103 extends beyond the outerperiphery of the corresponding pixel electrode 3, so that each colorfilter 101-103 (and layer 104) defines a greater surface area than thecorresponding pixel electrode 3. As a result of this difference insurface area, the layers 101-104 act as superior insulators, each with athickness of from about 1.0-3.0 μm in the areas 18 of overlap betweenthe pixel electrodes and the corresponding address lines, so as toreduce cross-talk and the coupling capacitance between the pixelelectrodes 3 and overlapped address line(s) in the high aperture LCD.

[0059]FIG. 4 is a side elevational cross-sectional view of a single TFT9 (in a red pixel) in the TFT array of the FIG. 1 AMLCD 2, with each TFT9 in the array being substantially the same as the one shown in FIG. 4according to certain embodiments. Each TFT 9 has a channel length “L”defined by the gap 27 between source electrode 15 and drain electrode13. Source electrode 15 is connected to pixel electrode 3 by way of viaor contact hole 35 defined in red color filter 101 so as to permit TFT 9to act as an isolating switching element and selectively energize acorresponding pixel/pixel electrode in AMLCD 2 in order to provide redimage data to a viewer. An array of TFTs 9 is provided as illustrated inFIG. 1 for the AMLCD, with the color filters being different colors indifferent color pixels. Alternatively, diodes may be used as isolatingswitching elements instead of TFTs.

[0060] Each TFT 9 structure includes substantially transparent activesubstrate 19 (e.g. made of glass), metal gate electrode 17, gateinsulating layer or film 21, semiconductor layer 23 (e.g. intrinsicamorphous silicon), doped semiconductor contact layer 25, drain iselectrode 13, source electrode 15, insulating color filter or layer 101,102, 103, or 104, and a corresponding pixel electrode 3. TFT channel 27of length “L” is defined between source 15 and drain 13.

[0061] Because the color filters (and layer 104) are patterned indifferent colored arrays on the active plate, the filters, as shown inFIG. 4, do not entirely overlap the whole drain electrode 13, butinstead only overlap a substantial portion (e.g. greater than about 25%of the drain electrode) thereof along with the TFT channel 27 so as toinsulate them from electrode 3 that also does not overlap the entiredrain electrode. As shown in FIG. 4, the pixel electrode 3 in each pixeldoes not even overlap the drain electrode in this embodiment, althoughit may in some embodiments. Optionally, in certain embodiments, thefilters 101-103, and layer 104, may overlap the entire TFT structure ineach pixel.

[0062] If the TFT structure illustrated in FIG. 4 was for the red pixelillustrated in FIG. 1, then the insulating layer 101 between the pixelelectrode 3 and the TFT and address lines would be red insulating colorfilter 101. Likewise, if the TFT structure illustrated in FIG. 4 was forthe green pixel of FIG. 1, then the insulating layer would berepresented by color filter 102, and if the TFT structure was for theblue pixel, then the insulating layer would be represented by blue colorfilter 103. If FIG. 4 was for a white pixel, the insulating layer 104would be clear. It is pointed out that the color filters 101, 102, 103,(and layer 104) cover the channel 27 of the TFT, but only partiallycover or overlap the corresponding drain electrode 13, 29 in certainembodiments.

[0063] As illustrated in FIG. 4, drain electrode 13 is made up of drainmetal layer 29 (e.g. Mo) which is deposited on active substrate 19 overtop of doped contact layer 25. Contact film or layer 25 may be, forexample, amorphous silicon doped with an impurity such as phosphorous(i.e. n+a-Si) and is sandwiched between semiconductor layer 23 and drainmetal layer 29. Source electrode 15 includes doped semiconductor contactlayer 25 and source metal layer 31. Metal layers 29 and 31 may be of thesame metal and deposited and patterned together according to certainembodiments of this invention. Alternatively, layer 29 may be depositedand patterned separately from layer 31 so that drain metal layer is ofone metal (e.g. Mo) and source metal layer 31 is of another metal (e.g.Cr) across the array.

[0064] FIGS. 6(a), 6(b), 6(c), and 11 illustrate AMLCD 2 according toanother embodiment of this invention [FIG. 11 does not show the pixelelectrodes 3]. This embodiment differs from the FIG. 1 embodiment inthat across substantially the entire display viewing area on the activeplate, the columns (or rows) of pixels between respective drain addresslines 5 extending in one axial direction are each of a single color. Forexample, as illustrated in FIGS. 6(a) and 11, column 111 of pixels onthe display area includes only red pixels with a single red color filterstrip 101, while column 112 of pixels includes only green pixels with asingle green filter strip 102, and column 113 includes only blue pixelswith a single blue filter strip 103. Therefore, red color filtermaterial 1 may be deposited and patterned on the active substrate into aplurality or array of elongated strips which correspond to the red pixelcolumns, thereby eliminating the need to pattern each red pixel filterindividually as a square. Therefore, because the materials 101-104 areonly patterned into elongated columns (or rows) extending in one axialdirection, gaps “P” exist over top of, and along the length of, one setof address lines, but not the other set which remains covered for themost part. The green and blue color filter materials 102-103 are alsopatterned into columns as illustrated.

[0065] As illustrated in FIGS. 6(a) and 11, gaps “P” between adjacentdifferent colored filter materials are present along substantially theentire lengths of the column lines (drain lines 5), while gate addresslines 7 are for the most part covered up entirely with the insulatingcolor filter materials, except for very small areas proximate the drainlines 5 where the gap “P” exists between adjacent color filters.

[0066] Referring to FIG. 6(a), each pixel also includes the storagecapacitor including contact hole 36 through which the correspondingpixel electrode 3 contacts the upper molybdenum electrode 12 of thestorage capacitor. The bottom electrode of each storage capacitor isformed by a gate line 7. FIG. 6(a) illustrates only three pixels, red,green, and blue, proximate one edge 121 of the viewing area. As will beappreciated by those of skill in the art, hundreds, if not thousands, ofdifferent colored pixels extended across the entire viewing area, witheach material 101-104 extending and being patterned into an array ofstrips across same. For example, red color filter 101 that isillustrated in FIG. 6(a) extends downwardly in direction 122 across theentire display viewing area (see FIG. 11), as do filter strips 102 and103. If white pixels are present, clear layer 104 strips will also beincluded. Also illustrated in FIG. 6(a) at the bottom of each of thethree pixels, are the storage capacitors which correspond to the coloredpixels below those illustrated.

[0067] Another difference between the FIG. 6(a)-6(c) embodiment relativeto the FIG. 1 embodiment, is that in the FIG. 6(a)-6(c) embodiment thegate electrode 17 of each TFT is formed as a perpendicular extensionwhich protrudes from a gate line 7. Meanwhile, the drain electrode 13 ofeach TFT is formed as a perpendicular extension which protrudes from theedge of a respective drain address line 5. Pixel electrodes 3 contactsource electrodes 15 through contact holes 35 which are illustrated inFIGS. 6(a) and 11 with “X” sectioning.

[0068]FIG. 6(b) is a side cross-sectional view of the active plate ofFIG. 6(a), taken along viewing line A-A with FIG. 6(b) also illustratingliquid crystal layer 45 and the common electrode 49 which is disposed onthe passive substrate 51.

[0069]FIG. 6(c) is a side cross-sectional view of the active plate ofFIG. 6(a), taken along viewing line BB.

[0070] Referring to FIGS. 1-11, color filters 101-103, and clear layer104, each have a dielectric constant less than or equal to about 5.0(preferably less than or equal to about 4.0, and even more preferablyless than or equal to about 3.0) according to certain embodiments ofthis invention, and are deposited and patterned on active substrate 19so as to at least partially cover the TFTs 9 and at least one of addresslines 5 and 7 in overlap areas. These low dielectric constant valueshave been found to reduce cross-talk and reduce line-pixel capacitancevalues, both of which are desirable results. For example, the red colorfilters 101 may be formed on substrate 19 by depositing red color filterlayer 101 and thereafter patterning same via known photolithographyand/or etching so as to form the-various red color filter strips orsquares 101 across the substrate in the red pixel areas. Thereafter thegreen color filter strips or squares 102 may be formed by depositing alayer of the green color filter material on substrate 19 and thereafterpatterning same via photo-imaging or the like so as to form the array ofgreen color filter strips or squares 102 on the substrate. The bluecolor filter strips or squares may be formed in a similar manner as maythe array of clear insulators 104.

[0071] Each color filter 101-103 may be formed of a color dye or pigmentinclusive photo-imageable material such as a filter material availablefrom Fuji [Olin Macroelectronics Materials, R.I.] known as ColorMosaic™, red, green, and blue, product Nos. CR-6200L, CG6030L, andCB-6030L respectively. The refractive index of each color filter is, forexample, for the red color filter 1.60, for the green 1.52, and for theblue 1.83. Generally, the refractive index of each color filter 101-103is from about 1.50 to 2.00. The photo-imageable nature of the colorfilters 101-103, and clear layer 104, permits vias or contact holes 35to be formed therein and also simultaneously allows the color filters tobe patterned on the active substrate. Optionally, vias or contacts holes36 may also be simultaneously formed in the color filters so as to allowformation of the storage capacitors.

[0072] Each color filter 101-103 (and material 104) is of a materialwhich has a dielectric constant ∈ less than or equal to about 5.0according to certain embodiments of this invention [at room temperatureand about 1 kHz as known in the art]. In certain preferred embodiments,each color filter layer has a dielectric constant less than or equal toabout 4.0 (even more preferably less than or equal to about 3.0). Incertain preferred embodiments, the clear layer 104 has a dielectricconstant ∈ of about 2.7 and may be made of a transparent photo-imageabletype of Benzocyclobutene (BCB), for the purpose of reducing capacitivecross-talk (or capacitive coupling) between the pixel electrodes and theaddress lines in overlap areas 18. Alternatively, the layer 104 may bemade of Fuji Clear™. Each color filter has a relatively low dielectricconstant and/or a relatively high thickness for the specific purpose ofreducing C_(PL) in the overlap areas. Alternatively, otherphoto-imageable dye inclusive materials having such low dielectricconstants may be utilized for color filters 101-103.

[0073] Following the deposition and patterning of the color filters101-103, and layer 104, on active plate 19 over top of the TFTs 9 andaddress lines 5, 7, vias 35 are formed in the color filters 101-103, andlayer 104, by way of either photo-imaging, wet etching, or dry etchingin other embodiments. The color filters and layer 104, inphoto-imageable embodiments, act as negative working resist layers sothat UV exposed areas remain on the substrate and areas unexposed to UVduring photo-imaging are removed during developing. Optionally, vias orcontact holes 36 may also be formed at this time. Following the formingof the vias or contact holes in the different patterned filters 101-103,and layer 104, substantially transparent pixel electrodes 3 (e.g. madeof indium tin oxide or ITO) are deposited and patterned over the colorfilters 101-103 and layer 104 on the active plate so that each pixelelectrode 3 contacts the corresponding source metal layer 31 of thecorresponding TFT 9 through a via 35 as illustrated in FIGS. 4 and 6.

[0074] The thickness of each color filter 101-103 (and layer 104) mayvary according to certain embodiments of this invention. For example,red color filters 101 may be thinner than green color filters 102 orvice versa, with blue 103 being thicker than both the red and greenfilters. In preferred embodiments, the thickness “d” of each colorfilter ranges from at least about 1.0 μm in overlap areas 18. In otherembodiments, the thickness “d” of each color filter is from about 1.0 to3.0 μm, and preferably from about 1.5-2.5 μm. The thickness of all ofthe strips or layers 101-104 may be substantially the same in certainembodiments.

[0075] Because of the low dielectric constant ∈ and/or relatively highthickness of each color filter 101-103 and layers 104, the capacitivecross-talk problems of the prior art resulting from overly high C_(PL)values are substantially reduced in overlap areas 18 where the pixelelectrodes 3 overlap the address lines and/or TFTs. Meanwhile, due tothe certain overlapping between address line(s) and color filters/pixelelectrodes, the possible liquid crystal disclinations at the pixel edgeswill be substantially overcome. Furthermore, the manufacturing of thesedisplays is improved (i.e. the total number and/or complexity of thesteps is reduced), as the number of total process steps on both activeand passive plates is reduced. Also, it is easier to align the opposingplates. Because the color filters are disposed between the pixelelectrodes and the address lines in the overlap areas 18, the capacitivecross-talk problems of the prior art are substantially reduced oreliminated, and increased pixel openings are achieved withoutsacrificing display performance (pixel isolation).

[0076] Pixel opening sizes or the pixel aperture ratio of AMLCD 2 is atleast about 65% (preferably from about 68% to 80%) according to certainembodiments of this invention when the pixel pitch is a reference ofabout 150 μm. The pixel aperture ratio will, of course, vary dependingupon the pixel pitch of the display (pixel pitch is from about 40 -500μm may be used). Pixel electrodes 3 overlap address lines 5 and/or 7along the edges thereof as shown in FIG. 1 by an amount of up to about3.0 μm. In certain preferred embodiments of this invention, the overlap18 of electrodes 3 over the edges of the address lines is designed to befrom about 2 to 3 μm, with the end result after over-etching being atleast about 0.5 μm. According to certain other embodiments of thisinvention, the amount of overlap may be designed to be from about 2-3μm, with the resulting post-processing overlap being from about 0.1 to2.0 μm. The overlap amount between the address lines and pixelelectrodes may be adjusted in accordance with different LCD applicationsand pixel pitch sizes as would be appreciated by those of skill in theart.

[0077] With regard to the overlap amount of the color filters 101-103,and layer 104, over the address lines 5, 7, the color filters 101-103,and layer 104, overlap the address lines to a greater degree than do thecorresponding pixel electrodes 3. For example, color filter 101 in thered pixel of FIG. 1 may overlap a corresponding address line (5 and/or7) by about 1.0 μm while the pixel electrode 3 of that pixel onlyoverlaps the same address line by about 0.5 μm. The patternedsubstantially co-planar arrays of filters 101-103 and layer 104 are allcharacterized by these traits.

[0078] In certain situations, after etching and processing, pixelelectrodes 3 may not overlap the address lines at all while the filtersdo still overlap the line(s) according to certain embodiments of thisinvention, although some overlap by both is preferred. When no overlapby the pixel electrodes 3 occurs, the parasitic capacitance C_(PL)between the address lines and the adjacent pixel electrodes 3 is stillminimized or reduced due to the insulating function of the color filters101-103 and clear layer 104, which do overlap the address lines.

[0079] Referring now to FIGS. 1-11, it will be described how AMLCD 2including the array of TFT structures and corresponding address lines ismade or manufactured according to one embodiment of this invention.First, substantially transparent active substrate 19 is provided. Next,a gate metal layer or sheet (which results in gate electrodes 17) isdeposited on the top surface (the surface which faces the liquid crystallayer) of substrate 19 to a thickness of from about 1,000-5,000 Å, mostpreferably to a thickness of about 2,500 Å. The gate metal sheet isdeposited by way of sputtering or vapor deposition. The gate metal maybe of tantalum (Ta) according to certain embodiments of this invention.Insulating substrate 19 may be of glass, quartz, sapphire, or the like.

[0080] The structure including active substrate 19 and the depositedgate metal is then patterned by photolithography to the desired gateelectrode 17 and gate address line 7 configuration. The upper surface ofthe gate metal is exposed in a window where the photoresist has not beenretained.

[0081] The gate metal (e.g. Ta) layer is then dry etched (preferablyusing reactive ion etching or RIE) in order to pattern the gate metallayer in accordance with the retained photoresist pattern. To do this,the structure is mounted in a known RIE apparatus which is then purgedand evacuated in accordance with known RIE procedures and etchants. Thisetching of the gate metal layer is preferably carried out until the gatemetal is removed in center areas of the window and is then permitted toproceed for an additional time (e.g. 20 to 40 seconds) of overetching toensure that the gate metal is entirely removed from within the windows.The result is the gate address lines 7 (and gate electrodes 17) beingleft on active substrate 19. In the FIG. 6 embodiment, the gateelectrode 17 are formed as extensions which protrude from the gate lines7, while in FIGS. 1 and 4 the gate electrodes are part of the actualgate lines 7.

[0082] After address lines 7 and electrode 17 are deposited andpatterned on top of substrate 19, gate insulating or dielectric layer 21is deposited over substantially the entire substrate 19 preferably byplasma enhanced chemical vapor deposition (CVD) or some other processknown to produce a high integrity dielectric. The resulting structure isshown in FIG. 7. Gate insulating layer 21 preferably includes siliconnitride but may also include silicon dioxide or other known dielectrics.Silicon nitride has a dielectric constant of about 6.4. Gate insulatinglayer 21 is deposited to a thickness of from about 2,000-3,000 Å(preferably either about 2,000 Å or 3,000 Å) according to certainembodiments.

[0083] It is noted that after anodization (which is optional), gate Talayer 17 which was deposited as the gate electrode 17 and gate line 7layer (when originally about 2,500 Å thick) is about 1,800 Å thick and anewly created Ta₂O₅ layer is about 1,600 Å. Anodization takes placeafter the gate line patterning and before further processing. Thus, gateinsulating layer 21 over gate lines 7 and electrodes 17 is made up ofboth the anodization created Ta₂O₅ layer and the silicon nitride layer.Other metals from which gate electrode 17 and address lines 7 may bemade include Cr, Al, titanium, tungsten, copper, and combinationsthereof.

[0084] After gate insulating layer 21 has been deposited, semiconductor(e.g. intrinsic a-Si) layer 23 is deposited on top of gate insulatinglayer 21 to a thickness of about 2,000 Å (see FIG. 8). Semiconductor 23may be from about 1,000 Å to 4,000 Å thick in certain embodiments ofthis invention. Then, doped (typically phosphorous doped, that is n+)amorphous silicon contact layer 25 is deposited over intrinsic a-Silayer 23 in a known manner as shown in FIG. 8 to a thickness of, forexample, about 500 Å. Doped contact layer 25 may be from about 200 Å-1,000 Å thick according to certain embodiments of this invention.

[0085] Gate insulating layer 21, semiconductor layer 23 andsemiconductor contact layer 25 may all be deposited on substrate 19 inthe same deposition chamber without breaking the vacuum in certainembodiments. When this is done, the plasma discharge in the chamber isstopped after the completion of the deposition of a particular layer(e.g. insulating layer 21) until the proper gas composition fordeposition of the next layer (e.g. semiconductor layer 23) isestablished. Subsequently, the plasma discharge is re-established todeposit the next layer. Alternatively, layers 21, 23, and 25 may bedeposited in different chambers by any known method.

[0086] Following the formation of the FIG. 8 structure, the TFT islandor area may be formed by way of etching, for example, so that the TFTmetal layers can be deposited thereon. Optionally, one of the TFT metalsource/drain layers may be deposited before forming the island.

[0087] According to certain embodiments, following the formation of theTFT island from the FIG. 8 structure, a source-drain metal sheet orlayer (which results in drain metal layer 29 and source layer 31) isdeposited on substrate 19 over top of semiconductor layer 23 and contactlayer 25. The result is TFT structure 9 with channel 27 (afterpatterning) is shown in FIG. 9.

[0088] Red color filter insulating layer 101 is then deposited ontosubstantially the entire substrate 19 by way of spin coating or printingaccording to certain embodiments of this invention. Layer 101 may be,for example, of red pigment or red dye inclusive photo-imageablematerial in certain embodiments. Layer 101 fills recesses generated uponformation of TFTs 9 and flattens the surface above substrate 19 at leastabout 60% according to certain embodiments.

[0089] The photo-imageable color filter layer 101 acts as a negativeresist layer according to certain embodiments of this invention so thatno additional photoresist is needed to pattern the layer 101 into thearray of red color filters 101 and to form vias 35 and/or 36 in thelayer. In order to pattern layer 101 and form vias 35 and/or 36, thelayer is irradiated by ultraviolet (UV) rays (e.g. I-line of 365 nm),with UV irradiated areas of layer 101 remaining on the substrate andnon-exposed or non-radiated areas of the layer being removed duringdeveloping. A mask may optionally be used. Thus, the areas of thenegative resist 101 corresponding to the vias and areas to be removedare not exposed to the UV radiation, while the rest of the layer whichwill result in the color filters is exposed to UV.

[0090] Following exposure of layer 101, the layer is developed by usinga known developing solution at a known concentration. In the developingstage, the areas of layer 101 corresponding to vias 35 and/or 36 and theremainder of the active area where the filter is not to be present areremoved (i.e. dissolved) so as to pattern the red color filters 101 onthe active substrate and form vias 35 and/or 36 in same. Afterdeveloping, the resist layer 101 is cured or subjected to post-baking(e.g. about 240° C. for about one hour) to eliminate the solvent so thatthe layer therein is resinified. Thus, no dry or wet etching is neededto form the vias and pattern layer 101 into the plurality of colorfilters 101 which take the form of strips in the FIG. 6 embodiment, andthe form of squares in the FIG. 1 embodiment. According to alternativeembodiments, layer 101 may be a positive resist as opposed to a negativeresist in photo-imageable embodiments. Alternatively, the color filterlayers may be non-photo-imageable in some embodiments.

[0091] Vias or contact holes 35 are thus formed in insulation colorfilters 101 over top of, or adjacent, each source metal electrode 31 soas to permit the corresponding pixel electrodes 3 to electricallycontact corresponding source electrodes 15 through vias 35 in the redcolor filters 101. The color filters remains across the entire area ofeach red pixel and each overlaps at least one of the adjacent addresslines as shown in FIG. 1.

[0092] After the red color layer 101 is formed and patterned on activesubstrate 19 as discussed above, the green and blue color filter layers102 and 103, respectively, are formed on the substrate 19 and patternedin the same manner so as to form the arrays of green and blue colorfilters 102 and 103 in the green and blue pixel areas of the AMLCD. Thegreen and blue color filters 102 and 103 are formed and provided on thesubstrate in a manner similar to the red color filters 101 discussedabove. Other clear strips 104 may be formed and patterned on substrate19 in a similar manner if white pixels are desired. Optionally, the redcolor filters do not have to be formed first. For example, the colorfilters could be formed in the following order: green, blue, and red; orblue, green, and red. Any order may suffice.

[0093] After all color filters are formed and patterned on substrate 19,a substantially transparent conducting layer (e.g. ITO) which results inpixel electrodes 3 is deposited and patterned (e.g. photo-masked andetched) on substrate 19 over top of the color filters. After patterning(e.g. mask and etching) of this substantially transparent conductinglayer, pixel electrodes 3 are left as shown in FIGS. 1, 3, 4, 5, and 6.As a result of the vias or contact holes 35 formed in the color filters,each pixel electrode 3 contacts a corresponding TFT source electrode 31.When contact holes 36 are provided, each pixel electrode 3 contacts astorage capacitor electrode 12. The result is the active plate of FIGS.1, 4, and 6, including an array of TFTs. The pixel electrode layer, whenmade of ITO, is deposited to a thickness of from about 300 Å to 900 Å(preferably about 600 Å ) according to certain embodiments of thisinvention. Other known materials may be used as pixel electrode layer 3.

[0094] The instant inventors have found surprisingly that the thicknessof the metal pixel electrode layer (and pixel electrodes 3) should befrom about 300 Å-900 Å in this invention, because of the need to reducethe interface stress between the pixel electrodes (e.g. ITO) andmaterials 101-104.

[0095] After formation of the active plate, liquid crystal layer 45 isdisposed and sealed between the active plate and the passive plate asshown in FIG. 5. The passive plate includes substrate 51, polarizer 53,common electrode 49, and orientation film 47. Meanwhile, the activeplate includes thereon polarizer 41, orientation film 43, and thestructure illustrated in FIGS. 1, 4, and 6 (noting that FIGS. 4 and 6are different embodiments).

[0096] As shown in FIGS. 1, 6(a), 6(b), and 6(c), the pixel electrodes 3and the color filters 101-103 (and layer 104) are patterned to a size sothat they overlap both drain address lines 5 and gate address lines 7along the edges thereof so as to result in an increased pixel apertureratio for AMLCD 2. The cross-talk problems of the prior art aresubstantially eliminated due to the presence of the color filters inoverlap areas 18 between the pixel electrodes and address lines.Alternatively, the pixel electrodes need only overlap one group ofaddress lines (e.g. column lines) according to certain embodiments.

[0097]FIG. 5 is a side cross-sectional view of AMLCD 2 (of FIG. 1 or ofFIG. 6), absent the TFTs, color filters, address lines, etc. As shown,the twisted nematic display includes from the rear forward toward theviewer, rear polarizer 41, substantially transparent active substrate19, pixel electrodes 3, rear orientation film 43, twisted nematic liquidcrystal layer 45, front orientation film 47, common electrode 49, frontsubstantially transparent substrate (passive substrate) 51, and finallyfront polarizer 53. Optionally, patterned black matrix/anti-refractivelayer may be inserted between substrate 51 and common electrode 49 inorder to reduce the possible refraction and/or reflection from theuncovered address lines, and shield TFTs from ambient light.Alternatively, a black matrix may be provided on address lines and TFTsbefore deposition of any polymer material is provided (i.e. on theactive plate). Polarizers 41 and 53 may-be arranged so that theirtransmission axes are either parallel or perpendicular to each other soas to define a normally black or normally white colored AMLCDrespectively. Optionally, retarders may also be provided between 19 andpolarizer 41 and/or 51 and polarizer 53.

[0098] Typically, a backlight is provided rearward of polarizer 41 sothat light emitted therefrom first goes through polarizer 41, thenthrough LC layer 45, and out of polarizer 53 toward the viewer. Pixelelectrodes 3 selectively work in conjunction with common electrode 49 soas to selectively apply voltage across LC layer 45 in different pixelsso as to cause an image to be viewed from the front of the display.

[0099] Exemplary line pixel capacitance values according to thisinvention range from about 4.5 to 10.0 fF when the overlap distance isfrom about 1-2μm. Compare these values with a conventional coplanar LCDin which the pixel electrodes are substantially coplanar with theaddress lines and spaced therefrom, such a conventional LCD having aline pixel capacitance of about 11.8 fF when the electrodes are spacedlaterally from the address lines by about 5 μm, and about 9.6 fF whenthe lateral spacing is about 10 μm. Thus the high aperture LCDsdiscussed herein have higher pixel aperture ratios than conventionalLCDs without suffering from substantially higher line pixel capacitancevalues. The capacitance values herein takes into consideration thefringing capacitance in a known manner.

[0100] The line pixel capacitance is less than about 20 fF, preferablyless than or equal to about 12 fF, and most preferably less than orequal to about 7.0 fF according to this invention with the overlappedareas and high pixel apertures.

[0101] The line-pixel capacitance values (and insulating materials) ofthis invention are similar to those disclosed in Chart 1 of U.S. Pat.No. 5,641,974, the disclosure of which is incorporated herein byreference.

[0102] The color filters disclosed herein have transmissioncharacteristics so that the pixels and LCD having viewingcharacteristics (e.g. contrast ratios and inversion characteristics) asdescribed in U.S. Pat. Nos. 5,594,568 and 5,570,214 when the retarderconfigurations claimed therein are used, the disclosures of which arehereby incorporated herein by reference.

[0103] Once given the above disclosure, many other features,modifications, and improvements will become apparent to the skilledartisan. Such other features, modifications, and improvements are,therefore, considered to be a part of this invention, the scope of whichis to be determined by the following claims.

We claim:
 1. A high aperture color liquid crystal display includingcolor filters, the display comprising: first and second substrates; aliquid crystal layer sandwiched between said first and secondsubstrates; first and second different colored pixels, said first pixelincluding on said first substrate a first pixel electrode, a firstinsulating color filter, and a first thin-film transistor (TFT), andsaid second pixel including on said first substrate a second pixelelectrode, a second insulating color filter, and a second TFT, whereinsaid first and second color filters are differently colored; said firstand second pixel electrodes overlapping corresponding address lines incommunication with respective TFTs so as to define a high aperturedisplay, said overlapping forming areas of overlap; said firstinsulating color filter being at least partially disposed in an area ofoverlap in said first pixel between said first pixel electrode and anaddress line, said first color filter having a dielectric constant ofless than about 5.0 and having a first contact hole defined therein thatallows said first pixel electrode to be electrically connected to saidfirst TFT; and said second insulating color filter being at leastpartially disposed in an area of overlap in said second pixel betweensaid second pixel electrode and an address line, said second colorfilter having a dielectric constant less than about 5.0 and having asecond contact hole defined therein that allows said second pixelelectrode to be electrically connected to said second TFT.
 2. The LCD ofclaim 1, wherein said pixel electrodes are conductive, and are of athickness of from about 300 Å-900 Å in order to reduce interface stressbetween the pixel electrodes and the color filters.
 3. The LCD of claim1, wherein said color filters are each formed of a negative resist. 4.The LCD of claim 1, wherein each of said color filters has a refractiveindex of from about 1.5 to 2.0.
 5. The LCD of claim 1, wherein thedielectric constant ∈ of each of said color filters is less than about4.0.
 6. The LCD of claim 1, wherein each of said color filters is of aphoto-imageable material.
 7. The LCD of claim 1, wherein each of saidfilters is from about 1.5-2.5 μm thick, and wherein said first pixelelectrode overlaps a first one of said address lines, said second pixelelectrode overlaps a second one of said address lines.
 8. The LCD ofclaim 1, wherein said color filters overlap said address lines to agreater extent than do corresponding pixel electrodes.
 9. The LCD ofclaim 1, wherein the pixel aperture ratio of the LCD is at least about68% and wherein each of said color filters is patterned into anelongated strip covering a plurality of pixels across the viewing areaof the display.
 10. The LCD of claim 1, wherein the areas of overlap arefilled with color filters, and the overlap areas have a width across theaddress lines of from about 0.1 to 2.0 μm in the overlap areas and thefilters are of a material and thickness so that the address line-pixelcapacitance is from about 4.5 to 10 fF.
 11. The LCD of claim 10, whereinthe capacitance is less than about 7.0 fF.
 12. A pixel having aphoto-imageable color filter in a liquid crystal display, the pixelcomprising: first and second substrates; a liquid crystal layersandwiched between said first and second substrates; a thin filmtransistor (TFT) provided on said first substrate including a gateelectrode, a drain electrode, and a source electrode; a first addressline provided on said first substrate, said first address line incommunication with said gate electrode; a second address line providedon said first substrate, said second address line in communication withsaid drain electrode; a pixel electrode provided on said firstsubstrate, said pixel electrode overlapping at least a portion of saidTFT and overlapping at least a portion of one of said address lines soas to define areas of overlap; a color filter insulating layer providedon said first substrate in said areas of overlap, said color filterinsulating layer having a dielectric constant ∈ less than about 5.0 anda thickness of at least about 1.0 μm in said areas of overlap; whereinsaid color filter includes a contact hole defined therein proximate saidsource electrode so that said pixel electrode electrically communicateswith said source electrode through said contact hole; and wherein saidcolor filter overlaps said address line(s) to a greater extent than doessaid pixel electrode.
 13. The pixel of claim 12, wherein said colorfilter is one of a red, green, and blue color filter, and wherein saidcolor filter has a dielectric constant of less than or equal to about4.0, and wherein said areas of overlap have a width of at least about0.5 μm.
 14. The pixel of claim 12, wherein said color filter is aresist, and includes a color pigment or dye, and a thickness of fromabout 1.5 to 2.5 μm in said areas of overlap.
 15. The pixel of claim 12,wherein said color filter is of a material and thickness such that aliquid crystal display including a plurality of such color filters canexhibit a white light contrast ratio of at least about 10:1 over ahorizontal angular span, at a predetermined vertical angle, of at leastabout 120° and over a vertical angular span of greater than about 50° ata predetermined horizontal angle when predetermined retarders areprovided in the display.
 16. The pixel of claim 12, wherein said colorfilter and said pixel electrodes each overlap at least a portion of saidfirst and second address lines, and wherein said color filter overlapseach of said address lines to a greater degree than does said pixelelectrode.
 17. The pixel of claim 16, wherein said color filter is of amaterial and thickness so that in one of said address line areas ofoverlap, the line-pixel capacitance is from about 4.5 to 10.0 fF whenthe length of said one area is a reference of about 100 μm.
 18. Thepixel of claim 12, wherein the pixel electrode has a thickness of fromabout 300 Å-900 Å.
 19. A method of making a color liquid crystal displayhaving strips of insulating color filters, the method comprising thesteps of: providing first and second substrates; providing a liquidcrystal material; forming an array of isolation switching elements onsaid first substrate and a plurality of address lines in communicationwith said isolation switching elements; depositing a first resist colorfilter layer on said first substrate over top of said address lines andsaid switching elements; photo-imaging said first resist color filterlayer so as to pattern it into a first array of elongated strips on saidfirst substrate so that color filters in said first array are of a firstcolor and overlap at least a portion of at least two address lines;depositing a second resist color filter layer of a second color over topof said first array of color filters; photo-imaging said second resistcolor filter layer so as to pattern it into a second array of elongatedstrips so that color filters in said second array overlap at least aportion of at least two address lines; depositing a third resist colorfilter layer of a third color over top of said first and second arraysof color filters; photo-imaging said third resist color filter layer soas to pattern it into a third of elongated strips array so that colorfilters in said third array overlap at least a portion of at least twoaddress lines; forming contact holes in color filters in each of saidfirst, second, and third arrays; depositing a conductive pixel electrodelayer over top of said first, second, and third arrays of color filters;and patterning said electrode layer so as to form an array of pixelelectrodes wherein pixel electrodes in said array overlap address lineswhich are also overlapped by color filters so that said color filtersact as insulators between said pixel electrodes and address lines inareas of overlap, and wherein each of said pixel electrodes is inelectrical communication with a corresponding switching element throughone of said contact holes, and wherein each of said color filters has agreater surface area than do corresponding pixel electrodes.
 20. Themethod of claim 19, wherein said method steps are performed in the orderin which they are recited, and each of said color filters has adielectric constant of less than or equal to about 4.0.